Method and apparatus for the production of music



Jan. 16, 1940., B. F. MIESSNER 2,187,612

METHOD AND APPARATUS FOR THE PRODUCTION OF MUSIC Filed July 22, 1958 2 Sheets-Sheet 1 CONE Jan. 16, 1940. B. F. MIESSNER 2,187,612

METHOD AND APPARATUS FOR THE PRODUCTION OF MUSIC Filed July 22; 1938 2 Sheets-Sheet 2 Patented Jan. 16, 1940 UNITED STATES METHOD AND APPARATUS ron THE PRODUCTION OF MUSIC Benjamin F. Miessner, Millburn, N. J., assig'nor to Miessner Inventions, Inc., Township of Millburn, County of Essex, N. .L, a corporation New Jersey Application July 22, 1938, Serial No. 220,722

20 Claims. (01. 84-1) This invention relates to the production of music, and more particularly to that production from vibrations of tuned vibrators. The invention has particular utility, and has been I illustrated and described, in connection with electronic instruments wherein the vibrations of the vibrators are translated into electric oscillations and thence into sound.

. It is well known that by such an instrument 10 there may be produced output tones of a variety of qualities. Many of these qualities may actually represent, or be the equivalent of, the superposition upon each other of two or more other qualities also available from the instrument' 15 yet the sensation of such superposition of separate qualities is ordinarily not impressed upon the bearer, who senses each produced quality as an integral or unitary one.

An important object of the instant invention I0 is the provision of improved methods and apparatus for producing, from a singleinstrument of the class described, output tones causing the sensation of a plurality of distinct instruments or voices playing simultaneously, or superposed on one another.

Another object is the production of such effects particularly by an electronic piano.

Another object is the provision of an instrument having a plurality. of vibrator-translation systems suitably differentiated from each other for the preservation of separate identity in the respective outputs of the several systems.

Another object is the provision in such an instrument of especially efiective combinations of difierentiating means.

Another object is the provision of improved means for differentiating the excitation of the vibrators.

Another object is the provision of improved control means, whereby there may be increased, with little complexity, the range of control of an instrument employing a plurality of vibrators per note.

It is a general object to-provide improvements in, and an improved, instrument of the class described. a

Other and allied objects will more fully appear from the following description and the appended a claims. Y

In .the description reference is had to the accompanying drawings of which:

Figure 1 is a view, partly in plan and partly diagrammatic, of an electronic piano wherein my invention has been incorporated in one form;

Figure 2 is a partial vertical cross-sectional view taken along the line 2-2 of Figure 1;

Figure 3 is a partial vertical cross-sectional view taken along the line 3-3 of Figure 1; and

Figure 4 is a view, partly in plan and partly 5 diagrammatic, of an electronic piano wherein my invention has been incorporated in a modified form.

Reference being had to Figures 1, 2 and 3,

there will be seen a fractional illustration of an instrument basically of the piano'type. In this instrument there are employed for each note a plurality of tuned strings I, maintained under tension between tuning pins and hitch pins not herein necessary to show; it may be mentioned, however, that the strings are maintained electrically insulated from each other and from common conductive elements, when the variable polarizing voltage hereinafter mentioned is employed. Near their rear extremities the strings may pass over and bear on a bridge 2 of wood or other insulating material, engaging respective pairs of bridge pins 3 in the top of the bridge in the usual manner. While the bridge may be variously supported, it is preferably disposed transversely of a plurality of vibratile ribs therebeneath; one such rib appears as l in Figure 2, 1 which illustrates a desirable extension of the bridge downward to the bottoms of the ribs sothat it maybe secured not only to the rib tops but also to the rib sides. By way of simple illustration the strings for each note have been shown as two in number, one of them being designated as l' and the other as I". Near their front extremities the two strings for each note, 5 which may at least here be relatively close together, may be struck, typically from beneath, by a hammer 5 respective to that note. Each hammer may be actuated by depression of a respective key 6, and depression of the key for 40 any note may also lift from the strings of that note a damper 1; these effects may be produced through conventional piano action mechanism not herein necessary to show. 7

With the several strings there are associated 5 means for translating their vibrations into electric oscillations, which after control and ampliflcation are translated into sound; and bile it will be obvious that my invention may a ried out with translating means of anyof a variety of types, I have particularly illustrated translating means of an electrostatic type, hereinafter more fully described.

According to a principal aspect of my invention,"

I employ a plurality of translating systems, sufficiently separate from each other so that each may provide individual qualitative control over the output tone components produced by it; each translating system is accordingly capable of supplying a respective one of the plurality of voices to be produced by the instrument. Were these translating systems associated in common with the same vibrators, however, there would occur, in large measure if not completely, a fusing or integration of these voices into a single composite voice-which, while actually representing the superposition of the plurality, would not be sensed as such by the bearer. According to the invention I associate each translating system with a respective vibrator or string for each of the several notes--e. g., I associate a translating system with the several strings i, and another translating system with the several strings I. This produces a plurality of distinct vibratortranslation systems wherein not only are the translation portions qualitatively differentiated from each other, but also the vibrator portions are inherently 'difierentiated from each otherat least to a slight extent by unavoidable minute differences between the strings of each note, and preferably to a greater extent by virtue of an actual slight detuning of those strings from each other. The efiect of these two differentiations, when jointly eifected, is to largely preserve the separate identity of the separate voices-or, in reverse terms, to suppress the sensation of their integration. A structure broadly involving a plurality of vibrators per note and separate translations therefrom was disclosed in U. S. Patent No. 1,933,294 to Jacobs; but that structure, being directed primarily to the selective production of diflerent types of tone and not to the preservation of voice individuality, contemplated neither deliberate slight detunings of the vibrators for .each note from each other, nor respective qualitative controls for the several translating systems, nor various other features of the instant invention hereinafter defined.

It will of course be understood that the showing of only two strings per note and two translating systems-i. e., of the strings i with their respective translating system and of the strings I" with their respective translating system-is only in the interest of simplicity of illustration, and obviously implies no limitaton to only two vibrator-translation systems.

In the instrument of Figures 1, 2 and 3 each translating system is arranged for the control of its voice in the qualitative respects of harmonic structure as influenced by particular partial components of each t0ne, of harmonic structure as influenced by absolute frequency, and of tone envelope shape (i. e., manner of inception and continuance of the tone), as well as in the quantitative respect of simple volume.

The control of harmonic structure as influenced by particular partial components has been illustrated as efiected by pick-up, or mechanico-electric translation, from each string at a plurality 8 secured across and between the ribs 4; such electrode mountings have been disclosed and claimed in my co-pending application Serial No. 187,646, filed January 29, 1938. i

.The several electrodes II' are connected together and to the upper extremity of a charging or polarizing resistance l3, while the several electrodes I! are connected together and to the upper extremity of a charging or polarizing resistance It. To simplify the electrode interconnections in the illustrated case of the use of two strings per note, the string I for one note may be made the rlghthand one, the string l' for the next note the lefthand one, and so on in an alternated or staggered arrangement; and toward their rear extremities the strings for each note may be fanned apart, to bring the strings I for successive notes relatively close together andthe strings I" for successive notes likewise relatively close together.

The lower ends of the resistances l3 and Il may be grounded (i. e., established at a reference potential), while the strings I may be suitably established at a potential difference from ground. Particular means for establishing this potential difference are hereinafter described; but it will be understood that however established, this potential difference during its continuance will polarize the minute capacities between the strings I and the electrodes ll through the resistance l3, and the minute'capacities between the strings I and the electrodes I! through the resistance I4. When these minute capacities are so polarized, their oscillatory variations by string vibration will cause substantially corresponding small oscillatory voltages to appear across the charging resistances, the waveform of the voltage across l3 substantially corresponding to the string vibrational waveform above electrodes II, and the waveform of the voltage across l4 substantially corresponding to the. string vibrational waveform above electrodes II.

The harmonically distinct voltages from the two resistances l3 and H are applied through respective input circuits l5 and it (each comprising for example series capacity and shunt resistance) to the respective repeater tubes II and I8, in the output circuits of which are connected the primaries of respective transformers IQ and 20'. Across the secondaries of these transformers are connected respective centertapped potentiometers 2| and 22', with centertaps connected together. The variable contacts Ila and 22a of these potentiometers are connected to a circuit or pair of conductors 23; and it will be understood (as disclosed in U. 8. Patent No. 1,906,607 to Jacobs) that by adjustment of the contacts 21a and 2241' the oscillations in circuit 23', translated from string l' vibration, may be controlled in respect of harmonic structure as influenced by particular partials of each tone.

The translating system for the strings i, continuing into circuit 23' as above described, is duplicated by a. translating system for the strings I", the components of the latter being designated by respectively similar numerals but with doubleprime marks. Thus underneath the strings I" there are provided electrodes I I" in the bridge extension 20 and electrodes I!" in the auxiliary bridge 8. The several electrodes H" are connected together and to the upper extremity of a charging resistance i3", while the several electrodes ii" are connected together and to the upper extremity of a charging resistance ll", the lower extremities of these resistances being grounded. Oscillatory voltages from across these resistances are applied to the respective repeater tubes l1" and I8", in the output circuits of which are provided the transformers and potentiometers ll"2 I and 20"-22" respectively. This translating system continues into a pair of conductors or circuit 23"; and it will be understood to function with respect to the strings I", and to provide an independent harmonic structure control for m the oscillations translated therefrom, as was described above for the translating system for the strings I.

Shielding, from external fields, of electrostatically sensitive portions of the translating systems I is of course desirably provided, and has been schematically indicated by the grounded enclosure S in Figure 1. It may also be desirable to provide some electrostatic shielding between electrodes of one of the translating systems and those oi the other; this has been schematically indicated in Figure'l as to the electrodes I2 and I2" by small grounded metal vanes V interposed therebetween, though it will of course be understood that no limitation to use only with these electrodes is intended.

For the separate control, tor the two translating systems, of harmonic structure as influenced by 'absolute frequency, there are schematically shown as interposed, in the circuits 23 and 23" a of the respective translating systems, the respective control circuits 2! and 24"; these may operate independently to control the transmissionfrequency characteristics of the circuits 23' and 23". Beyond the control circuits 24' and 24", a the circuits 23' and 23" may be connected together, serially for example, to merge the differentiated oscillation outputs of the two vibratortranslation systems forcommon final amplification and common control. Thus these here-interconnected circuits may feed into a cascade of appropriate apparatus schematically shown as amplifier 25, control circuit 26 '(which may effect volume control, and if desired transmissionfrequency control, for the combined oscillations), further amplifier 21. and loudspeaker 28.

For separate control of the tone envelope shape in connection with the respective translating systems, there may be employed with each a respective system for the control of translation em ciency-.-ior example, a polarizing voltage control system of the type disclosed in U. S. Patent No. 2,071,649 to Miessner et al. Such a system for the translating system associated .with the strings l'- may include a plurality of single-pole doublethrow switches 3|, each having a pole which is mechanically connected with the respective key 6 to be thrown from its lower. contact to its upper -contact upon key depression. The lower contacts of all the switches 3| are connected totentiometer 33', while the upper contacts of all the same switches are connected together and to the variable contact 33b of the same potentiometer; the potentiometer is connected across a battery or other-source of high potential 34, one extremity of which is grounded. The strings I' normally have the potential which is established by the adjustment of contact 33a; but upon depression of any key 6, the throwing of the associated switch 3!. will cause the associated string I to take on the potential established by the adjustment of the contact 33b. The change of I string potential is rendered slightly gradual, rather than wholly abrupt, by an electrical time-delay system 32', an individual such system being gether and to the variable contact 33a of a poserially interposed between each string l' and the associated switch pole, as schematically indicated in Figure 1.

excitation, it will provide a regulation of the tone envelope. Purely by way .of example, if the con;- tact 33a be adjusted to the grounded extremity and the contact 33b to the ungrounded extremity of the potentiometer 33, the strings i will normally be kept at no potential difference from the electrodes II and I2, and translation efiiciency for those strings is normally zero; but as depression of any key is completed and the as-- sociated string l' excited, the potential difference and translation efficiency as to that string will rise at a rate determined by the associated timedelay system 32', and the produced tone will have a generally organ-like inception in spite of the impulse excitation of the string.

The tone envelope control system for the strings i' is duplicated by a similar system for the strings I the components of the latter system being designated by respectively similar numerals but with double-prime marks. Thus the switches 3|" are provided, each having a pole mechanically connected with a respective key 8 and electrically connected, through a respective time-delay system 32", to the respective string I". The lower contacts-of the switches 3|" are connected to the variable contact 33a", and the upper contacts of the same switches to the variable contact 33b", f the potentiometer 33", which potentiometer may be parallel with the potentiometer 33'. By way of example of an adjustment for different tone envelope from the strings I and their associated translating system than from the strings I and their associated translating system, the variable contact 33a" has been shown adjusted to the high-potential extremity of the potentiometer 33" and the variable contact 33b" to an intermediate point on that potentiometer. With this adjustment the translation efllciency for the strings I" is normally high but will be reduced to a partial extent, at a finite rate, immediately after tone inception; accordingly there is produced a tone having an impulsive o'r pianistic inception characteristic, that characteristic being especially emphasized by the immediately ensuing partial reduction above mentioned. It will be understood, of course, that the particular adjustments in which the several contacts 33a33b' and 33a33b" have been illustrated are exemplary only, and that each pair is intended to be adjusted as desired, to produce-for example any of a range of 'eflects such as described in the Patent No;

2,071,649 abovementioned.

In addition to the qualitative diflerentiations, between the voices, provided by the separate controls in the translating portions of the several vibratortranslation systems, differentiations may be efiected in the vibrator portions of those systems. One such differentiation may be in respect of the rate of damping-the strings of one of the groups I and I" being for example subjected to higher damping influences than those of the other. This has been schematically illustrated in the instrument of Figures 1, 2 and 3 by the fractional showing of, coatings l! surrounding the strings I. These coatings may be of felt dust or similar light and fluily material, held in a thin layer of lacquer or other cementitious material preferably itself characterized by internal resistance to deformation; in this way both air damping and internal-resistance damping may be obtained, though it willv be understood that either alone may be found sufiicien-t to produce a marked difierentiation in damping rate between the two groups of strings. Such coatings of strings have themselves been disclosed and claimed in my co-pending application Serial No.

187,646 abovementioned.

Another such-differentiation may be eiiected bydifferently exciting the strings of the two groups I' and I"; in Figures 2 and 3 I show two portions andi" illustrate a manner of carrying out the sharpness variation.

Another way-of causing the diiierent excitationis by arranging the hammers and strings so thatthe striking of the strings I and I" is progressive, in point of time or of strength or of both. In Figure 3 the bevelling of the tops of the lefthandtwo hammers, and the arrangement at diflerent-elevational levels of the two strings of each of the righthand two notes, illustrate two manners of causing the excitation or striking of the strings I" to be'progressively earlier and stronger than that of the strings I. It may be pointed out that the differentiation by progressive excitation has the .further effect of increasing the touch-responsivity of the instrument, and that by the touch on the individual keys the contribution of the voice from strings I' may be especially effectively controlled--it being noted that while for very weak strikings the strings I" will be moderately excited, the strings I will be excited negligibly or not at all.

In Figure 4 I illustrate my invention in a modifled embodiment, again by way of example employing translating systems of an electrostatic type, but withthose systems arranged in materiallydiiie'rent circuits and without tone envelope control. In this embodiment each string I is shown as the lefthand one, and each string I" as the righthand one, of its respective note; and the strings 01 each note have been shown as fanning only slightly apart rearwardly. In this embodiment all the strings may be electrically connected together, in any convenient manner, and to ground. The usual key-hammer-damper system has been fractionally illustrated by the showing of a respective hammer 5 under the pair oi strings for each note.

The translating system for the strings I again includes, under those strings, the interconnected electrodes II' in bridge extensionla and the interconnected electrodes I2 in auxiliary bridge I; while the translating system for the strings I again includes, under those strings, the interconnected electrodes II" in bridge extension 2a and the interconnected electrodes I 2"- in auxiliary bridge 8. In view of the string arrangementabovementioned, the singleand double-primed electrodes are of course wholly alternate. The translating system for the strings I' further includes a charging or polarizing resistance 43 connecting the electrodes II with the variable contact a'of a potentiometer 45, and a charging or polarizing resistance 44 connecting the electrodes I2 with the variable contact 46a of a potentiometer 46'; whilethe translating system for the strings I further includes a charging or polarizing resistance 3 connecting the electrodes II with the variable con'tact 45a" of a potentiometer 45", and a charging or polarizing resistance 4|" connecting the electrodes I2" with the variable contact 460." of a potentiometer 46". Each of these four potentiometers may be provided with a grounded center-tap, and its variable contact may be taken as normally freely adjustable, independent of the position of the like contacts on any of the other potentiometers.

Direct voltages are maintained across these four potentiometers as hereinafter more fully described. It will be understood that by adjustment of the contacts 450. and 46a there may be diflerentially adjusted (as to both amplitude and polarity) the polarizing voltages for the minute capacities between strings I' and the two sets of therewith associated electrodes; likewise that by adjustment of the contacts 45a and in there may be,difierentially adjusted the polarizing voltages for the minute capacities between strings I" and the two sets of therewith associated electrodes. These minute capacities being varied by string vibration, there are developed across the resistances 43' and 44', considered as a pair, oscillations translated from the strings I and having a controlled harmonic structure (as influended by particular partials); likewise there are developed across the resistances 43 and 44', considered as a pair, oscillations translated from the strings I" and having an independently controlled harmonic structure. These oscillations may be merged for-common amplification and further control, by application through condensers 49, 50, 49", 50 to a common load resistance 5|; from this they may be applied through input circuit 52 to a repeater tube 53, in the output circuit of which may be connected the cascade 25-26-'-2128 as in Figure 1.' It will be obvious that there is thus provided an instrument wherein vibrators excited in common, but slightly detuned or otherwise differentiated from each other, are translated from by systems independently adjustable as to harmonic structure of'their produced tones, so that the effects of distinct, controlled voices are again obtained.

The control by contacts 45a and 46a of simple volume and phase of the contribution from the strings I, or the control by contacts 45a and 46a" of that from the strings I", would in either instance require a careful joint adjustment of those two contacts. To obviate the necessity of this I have shown the direct voltage impressed across the potentiometers 45 and 46' by the connection of these potentiometers between the center-tap 41c and the variable contact 4111 of a potentiometer ll shunted across a high voltage source or battery 48, and the direct voltage impressed across the potentiometers 45 and 46" by the connectionof those potentiometers between the center-tap 41c and the variable contact 41a" of the potentiometer 41. Control of simple volume and phase of the contributions [from the two sets of strings may accordingly be effected simply by adjustment of the respective contacts 41a and 41a".

anem a schematically illustrated a means for effecting tact with the respective strings I, t0' provide at will an adjustable damping of those strings; it is of the two vibrator-translation systems,

at will a qualitative diiferentiation, in respect of damping rate, between the vibrator portions Thus transverse of and beneath the strings, near their forward extremities, there may bedisposed a rail 55, arranged for limited rightward and leftward sliding, and constrained as by spring 56 pressing thereagainst to remain in any position to which it may be adjusted; and from this rail there may extend upwardly at the left of each string I a respective small pad 51 of felt or other soft material. By a sliding of the'rail 55 the several pads 51 may be'brought into or out of light conto be-understood, however, that this particular adjustable damping means is shown purely by way of example and in no sense as limitatively.

At times it may be desired to suppress the effect of separate voices from the instrument, while retaining the activity of all the vibrator-translation systems. In the instrument of Figure 4 I have'schematically illustrated two mechanical coupling devices 51 and 58, operable at will to couple the variable contact 450 on potentiometer to the contact 450/ on the potentiometer 45", and the variable contact 461;" on potentiometer 48 to the contact 46a" onfthe potentiometer 46", respectively. It will be understood that when these coupling. devices are in operation each pair of thecoupled contacts willbe adjusted as a unit, rendering entirely .similar the harmonic structures of the oscillations produced by the two vibrator-translation systems and thus unifying the voices.

When these coupling devices are in operation the instrument of Figure 4 may be employed in the general manner of operation disclosed in U.-

S. Patent No. 1,912,293 tome, but with features of improvement thereover. This general manner of operation involves the simultaneous excitation of two vibrators, one preferably having a higher rate of damping than the other, and translations therefrom with similar harmonic structures but respectively "opposite. phases. Thereby two series of oscillations are produced, of which at first one substantially wholly cancels the other; but as the one dies away the cancelling eiTect decreases, and the overall effect is of a gradually or smoothly beginning-rather than an impulsively or pianistically. begimringtone. The mentioned patent showed that this action'could be eliminated at will, and the tone rendered pianistic, by making the twotranslations of additive rather than of opposite phase,

and preferably eliminating the damping of the one vibrator. I

I have found, however, that with such a circuit as that of the instant Figure 4 (employed with the coupling devices 51 and 58 operative) I am able toobtain a far wider range of useful effects. The variable contacts 41a .and .4111",

being adjustable progressively (i. e., conti nuous- .ly or at least to a plurality of voltage values) make it possible to obtain not only the two types of tone last abovementioned, but also tones of accentuated percussiveness' and tones of reduced percussiveness. For each of these types of tone the dampers are rendered active-on the strings i; the contact 41a" is adjusted to a first voltage value; and the contact 41a is adjusted to that voltage value, of the same or opposite polarity according to which of the tone types is wanted,

cussiveness' which yet have a long continuance at low. ampltiude (due to the undamped strings While in connection with the instruments abovementioned I have disclosed the several strings for each note as substantially similarly tuned or only slightly detuned from one another (for example, to the extent of the general order of 1% or less), it may be pointed out that various special effects maybe obtained bytuning the several strings for each note to respective frequencies harmonically or harmoniously related to each otherfor example in the case of two strings, in the frequency ratio of 1:2 or 1:3 (a harmonic relationship) or in the frequency ratio of 1:1 or 1:1 (a harmonious relationship), or the like.

While I have disclosed my invention in terms of particular embodiments thereof, it will be understood that as to its broader aspects I intend no unnecessary limitations by virtue of the details of those embodiments, which obviously may,

I be widely varied without departing from the spirit and scope of the invention. In many of the appended claims I undertake to express that scope broadly, subject however to such proper limitations as the state of the art may impose.

I claim: 1. A musical instrument for the production of ,a series of notes, having for each note a plural-.

ity of slightly detuned vibrators; means associated with the vibrators of each note for exciting the same; mechanico-electric translating means, comprising a plurality of translating systems each associated with a respective vibrator of each of the several notes; and means, connected with said translating means, for difleren- .tially controlling qualitative characteristics of the oscillations translated by the respective said systems.

2. A- musical instrument for the production of a series of notes, having for each note a plurality of slightly detuned vibrators; means associated with the vibrators of each note for exciting the same; mechanico-electric translating means, comprising a plurality of translating systems each associated with a respective vibrator'of each of the several notes; and means, connected with said translating means, for differentially controlling the harmonic structures of the oscillations translated by the respective said systems.

3. A musical instrument for the production of a series of notes, having for each note a plurality of slightly detuned vibrators; means associated with the vibrators of each note for exciting the same; mechanico-electric translating means, comprising a plurality of translating systems each associated with a respective vibrator of each of the several notes; and means, connected with said translating means, for difierentially controlling the envelope characteristics of the oscillations translated by the respective said systems.

4. A musical instrument for the production of a series of notes, having for each note a plurality of slightly detuned vibrators; means associated ,with the vibrators of each note for exciting the same; mechanioo-electric translating means,

comprising'a plurality oi? translating systems each associated with a respective vibrator of each of the several notes; and electrical means for difl'erentially controlling qualitative characteristics of the oscillations translated by the respective said systems.

5. An electronic piano for the production of a series of notes, having for each note a plurality 10 ofsubstantially similarly tuned strings; means associated with the strings of each note for ex citing thesame; a plurality of mechanico-electric translating systems each associated with a respective string of each of the several notes; and a plurality of means, respectively connected with the several said systems, for individually controlling qualitative characteristics of the oscillations translated by the respective said systems.

6. An electronic piano for the production of a series of notes, having for each note a plurality of substantially similarly tuned strings; means associated with the strings of each note for exciting the same; a plurality of mechanico-electric translating systems each associated with a respective string of each of the several notes; and

a plurality of means, respectively connected with the several said systems, for individually controlling the harmonic structures of oscilla- 80 tions translated by the respective said systems.

'7. An electronic piano for the production of a series of notes, having for each note a plurality of substantially similarly tuned strings; means associated with the strings of each note for exciting the same; a plurality of mechanico-electric translating systems. each associated with a respective string of each 01' the several notes; and a plurality of means, respectively connected with the several said systems, for individually controlling the envelope characteristics of the oscillations translated by the respective said systems.

8. A musical instrument comprising a plurality of vibrator-translation systems, each system comprising a plurality of vibrators respectively slightly detuned from corresponding vibrators in each other system and mechanico-electric translating means associated therewith and responsive to the vibrations thereof; a plurality of vibrator-exciting means, a respective one of said exciting means being associated with corresponding vibrators in the several said systems; and means included in at least one of said systems for diiierentiating qualitative characteristics of the oscillations produced thereby from those produced by other of said systems.

9. A musical instrument comprising a plurality of vibrator-translation systems, each system comprising a plurality of vibrators respectively slightly detuned from corresponding vibrators in each other system and mechanico-electric translating means associated therewith and responsive to the vibrations thereof; a plurality of vibrator-exciting means, a respective one of said exciting means being associated with corresponding vibrators in the several said systems; means influencing the vibrators of at least one of said systems for differentiating qualitative characteristics of their vibrations from those of the vibrators of other of said systems; and means associated with the translating means of at least one of said systems for difierentiating qualitative characteristics of the oscillations produced thereby irom those produced by other of said systems.

10. A musical instrument comprising a plural- 7a ity of vibrator-translation systems, each system comprising a plurality of vibrators respectively substantially similarly tuned to those oi each other system and mechanico-electric translating means associated therewith and responsive to the vibrations thereof; a plurality of means. a respective one of which is associated with corresponding vibrators in the several said systems. for differently excitingcorresponding vibrators; and means associated with the translating means of at least one of said systems for differentiating qualitative characteristics of the oscillations produced thereby from those produced by other of said systems.

11. In a musical instrument, the combination of a plurality of substantially similarly tuned vibrators; means for translating sound of different qualitative characteristics from said vibrators respectively; a movable key; and impulse exciting means, operated by said key in a single movement thereof, for exciting said vibrators progressively in point of time. I Y

12. In a musical instrument, the combination of a plurality of substantially similarly tuned vibrators; means for translating sound of difierent qualitative characteristics from said vibrators respectively; a movable key; and impulse exciting means, operated by said key in a single movement thereof, for exciting said vibrators progressively in point of excitation strength.

13. In a musical instrument, the combination of a plurality of substantially similarly tuned vibrators; means for translating sound of difierent qualitative characteristics from said vibrators respectively; and a hammer movable to strike said vibrators, the striking surface of said hammer being bevelled to strike one of said vibrators prior to the other.

14. In a musical instrument, the combination of a plurality of substantially similarly tuned vibrators; means for translating sound of different qualitative characteristics from said vibrators respectively; and a hammer movable to strike said vibrators, one of said vibrators being nearer than other of said vibrators to said hammer to be earlier struck.

15. In a musical instument, the combination ,of a plurality of substantially similarly tuned vibrators adjacent each other; means for translating sound of different qualitative characteristics from said vibrators respectively; and a hammer movable to strike said vibrators, the portions of said hammer striking said vibrators respectively being substantially different in hardness.

16. In a musical instrument, the combination of a plurality of substantially similarly tuned vibrators adjacent each other; means for translating sound of diflerent qualitative characteristics from said vibrators respectively; and a hammer movable 'to strike said vibrators, the portions of said hammer striking said vibrators respectively being substantially different in sharpness.

17. In a musical instrument, the combination of two substantially similarly tuned vibrators; means for damping one of said vibrators; means for translating electric oscillations from the vibrations of each of said vibrators; and .progressively adjustable means for opposing regulable amplitudes of the oscillations translated from one of said vibrators against oscillations translated from the other.

18., In a musical instrument, the combination of two substantially similarly tuned vibrators; means for damping one of said vibrators; means for. translating electric oscillations from the vibrations of each of said vibrators; and progressively adjustable means for selectively opposing and adding regulable amplitudes of the oscillations translated from one of said vibrators against and with oscillations translated from the other.

19. In a musical instrument, the combination of' a tuned vibrator; a plurality of electrodes in spacedrealtion thereto and forming therewith a means for differentially controlling the relative varying the absolute values of said voltages while.

maintaining their relative values.

20. A musical instrument for the production of a series of notes, having for each note a plurality of substantially similarly tuned vibrators; means associated with the vibrators of each note for exciting the same; a plurality of mechanico-electrio translating systems each associatedwith a respective-vibrator of each of the several notes;

a plurality of means for individually controlling qualitative characteristics of the oscillations Y translated by the respective said systems; and

" common for said plurality of systems.

EENJABMN F MIESSNER. 

